TABLE 3.

Death rates (per 1,000 person-years) by BMI category in three US mortality studies, ages 50–74 at baseline

	Framingham			NHANES			NHIS
	Original cohort	Offspring cohort	p for trend	NHANES I	NHANES III	p for trend	Period 1	Period 2	p for trend
Overall	16.7 [15.5–17.9]	11.3 [10.3–12.3]	<.001	26.0 [24.4–27.8]	24.7 [23.0–26.5]	.29	20.1 [19.5–20.7]	15.7 [15.1–16.2]	<.001
BMI category
Underweight	33.3 [13.2–53.4]	30.6 [5.8–55.5]	.87	61.1 [43.4–78.7]	61.8 [37.0–86.6]	.96	41.4 [36.3–46.6]	31.7 [23.3–40.0]	.05
Normal weight	16.6 [14.7–18.4]	10.1 [8.5–11.7]	<.001	25.7 [23.0–28.4]	24.0 [21.4–26.5]	.35	19.8 [19.0–20.7]	17.0 [16.1–17.9]	<.001
Overweight	15.0 [13.3–16.8]	11.3 [9.8–12.9]	.002	21.1 [18.6–23.8]	24.0 [21.1–26.9]	.15	18.3 [17.4–19.1]	13.8 [13.0–14.6]	<.001
Class I obese	20.4 [16.8–23.9]	11.9 [9.4–14.4]	<.001	33.5 [26.6–40.4]	22.6 [19.7–25.4]	.01	21.2 [19.5–22.9]	15.5 [14.1–16.8]	<.001
Class II/III obese	21.3 [14.2–28.3]	15.7 [10.6–20.8]	.21	29.1 [21.6–36.6]	29.8 [24.5–35.2]	.87	26.5 [23.0–30.1]	19.2 [16.7–21.7]	<.001

NOTE: Rate per 1,000 person-years [95% confidence interval] unless otherwise noted. Results for NHANES and NHIS reflect sample weighting. Sample sizes are unweighted in all data. Weight status categories: underweight (BMI <18.5), normal weight (BMI 18.5–24.9), overweight (BMI 25.0–29.9), class I obese (BMI 30.0–34.9), class II/III obese (BMI ≥35.0).